Typically, flame spraying devices are equipped with some type of coupling for detachably securing a metallic powder container thereto and operable to dispense powder at a suitable rate into the torch flame for fusion to a metal object being coated therewith. Customarily, the powder is stored in shipping containers of convenient size for attachment to the torch. Frequently only a portion of the container contents is required for a particular operation. Heretofore, such containers have inadequate and unsatisfactory provision for safeguarding against the loss of the costly powder during assembly and disassembly of the container to and from the torch. Usually the powder feeds by gravity from a storage position overlying the main body of the torch.
If the torch is not fixedly mounted the operator can invert it in one hand while using the other to hold the container and to manipulate its coupling. This is awkward and cumbersome if the user must use the one hand to hold both the container and to manipulate the clamping assembly as is true of the construction proposed in the patent to Wett U.S. Pat. No. 2,671,689. Other designers propose powder containers utilizing telescopic bayonet type coupling means, such as the expedients proposed in Lamb U.S. Pat. No. 2,957,630; Broderick et al U.S. Pat. No. 3,252,628; Broderick U.S. Pat. No. 3,620,454 and Huhne et al U.S. Pat. No. 3,986,668. Each of these prior constructions involves the loss of objectionable quantities of costly hardfacing powders in those cases wherein the torch is fixedly supported relative to the work undergoing hardfacing. This is occasioned by the fact that powder flows from the container by gravity into the inlet end of the powder feed tube. It follows that there is an unavoidable loss of powder from the container feed passage which occurs while the inverted container is being assembled to and disassembled from the torch. Broderick et al U.S. Pat. No. 3,252,628 does propose an expedient for safeguarding against loss during insertion of the powder feed tube into a fully charged container but includes no provision for preventing powder loss during removal of a partially empty container.